J. Aquat. Plant Manage. 44: 73-80 Evaluating the Feasibility of Planting Aquatic Plants in Shallow Lakes in the Mississippi Delta PETER C. SMILEY, JR.1 AND ERIC D. DIBBLE1 ABSTRACT planting seeds, propagules (stems and tubers), or whole plants. Previous work has found that planting whole plants is Planting aquatic plants is a technique used to restore na- the most effective method of establishing aquatic plants in tive aquatic plants in lakes. However, the feasibility of using lakes and wetlands (Hammer 1992, Smart et al. 2005). How- this restoration technique in shallow lakes in the Mississippi ever, planting whole plants is a time consuming and costly Delta has not been evaluated. We conducted two exclosure procedure (Hammer 1992). Time and expense can be used experiments to evaluate the success of planting aquatic plants most efficiently if project designers know which plant species in a shallow lake in the Mississippi Delta. We planted three will exhibit the greatest survival and growth before the initia- emergent and one submersed species in experiment 1 and tion of planting. four submersed species in experiment 2. Each experiment The feasibility of planting aquatic plants in lakes and res- contained a control treatment in which no aquatic plants ervoirs in the southern United States has been evaluated in were planted. We measured physico-chemical characteristics Alabama, Oklahoma, and Texas (Table 1). Initial studies in of sediment and water and monitored aquatic plants in each Alabama and Texas (Doyle and Smart 1993, Doyle et al. exclosure. No differences in mean sediment and water pa- 1997, Smart et al. 1998) focused on the feasibility of planting rameters were observed among planting treatments in either submersed aquatic plants with limited efforts devoted to experiment. Squarestem spikerush (Eleocharis quadrangulata emergent aquatic plants (Table 1). Recent work in Oklaho- (Michx.) Roemer & J.A. Schultes) and arrowhead (Sagittaria ma and Texas (Dick et al. 2004a, b) expanded evaluation ef- latifolia Willd.) exhibited the greatest mean percentage cover forts by examining the planting success of an additional and the lowest probably of extinction in experiment 1. Addi- eight emergent species and 11 submersed species (Table 1). tionally, blunt spikerush (Eleocharis obtusa (Willd.) J.A. Schult- All 15 aquatic plant species recommended as candidate spe- es) and squarestem spikerush had the greatest mean stem cies for restoration projects (Smart et al. 1996, Smart et al. density in experiment 1. Only mean percentage cover dif- 2005) have been evaluated at least once (Table 1). Specifical- fered among planting treatments in experiment 2, and fra- ly, American eelgrass (Vallisneria americana Michx.) and grant water lily (Nymphaea odorata Ait.) exhibited a greater American pondweed (Potamogeton nodosus Poir.) were the mean percentage cover than the control. Our results suggest most frequently evaluated species (Table 1). Unfortunately, a that the squarestem spikerush and fragrant water lily may be synthesis of the results of previous evaluations is lacking and the best candidate species for aquatic plant restoration limited guidance is available regarding the selection of can- projects in shallow lakes within the Mississippi Delta. didate species for restoration efforts. Key words: lakes, littoral zone, restoration, aquatic plants, Many lakes in the Mississippi Delta are impacted by sedi- active planting, Mississippi. ment, pesticides, and herbicides as a result of extensive agri- cultural land use in the region (Duda and Johnson 1984, INTRODUCTION Guedon and Thomas 2004, Miranda and Lucas 2004). The restoration of aquatic plants within these lakes may reduce One past paradigm with respect to restoration of aquatic turbidity and the amounts of pesticides and herbicides plants in lakes has centered on the removal of non-native (Bouldin et al. 2004), and provide habitat structure and refu- aquatic plants with little consideration for the reestablish- gia for aquatic organisms (Dibble et al. 1996). However, in- ment of native aquatic plants (Barko et al. 1986, National Re- formation on the feasibility of planting aquatic plants in search Council 1992). Undoubtedly, removal of non-native Mississippi lakes is lacking (Table 1), and the high turbidity plants will continue to be an integral component of future levels typically found in shallow lakes in the Mississippi Delta restoration projects, but the focus needs to shift to the estab- may limit the establishment of aquatic plants. Therefore, we lishment of native aquatic plants (Barko et al. 1986, National conducted two exclosure experiments from June to Septem- Research Council 1992). Planting aquatic plants is one tech- ber 2002 to evaluate the success of planting aquatic plants in nique used to restore aquatic plants in lakes and wetlands. a shallow lake in the Mississippi Delta. Our objectives were to Specifically, aquatic plants can be established in lakes by evaluate: (1) the success of planting three emergent species and one submersed species in portions of the littoral zone that dry out during summer low water levels (experiment 1) Department of Wildlife and Fisheries, Mississippi State University, P.O. and (2) the success of planting four submersed species in Box 9690, Mississippi State, MS 39762. 1 Corresponding author’s present portions of the littoral zone that remain inundated all year address: USDA-ARS, Soil Drainage Research Unit, 590 Woody Hayes Drive, Columbus, OH 43210; e-mail: [email protected]. Received for publication (experiment 2). We measured selected sediment and water February 20, 2006 and in revised form April 17, 2006. parameters to assess whether differences in physical habitat J. Aquat. Plant Manage. 44: 2006. 73 TABLE 1. EMERGENT AND SUBMERSED PLANT SPECIES EVALUATED FOR FEASIBILITY 1982). The levee system prevents surface runoff into the OF PLANTING IN SOUTHERN LAKES AND RESERVOIRS, AND THE LOCATION (STATE) lake, and hydrology is maintained by rainfall and a pump WHERE EVALUATIONS WERE CONDUCTED. and drain system. Two groundwater pumps draw water into Emergent species State the lake, and two drains allow the release of water from the lake. Past aquatic plant management efforts were designed Bacopa monnieri (L.) Pennell OK4, TX5 to reduce excessive amounts of coontail (Ceratophyllum demer- Echinodorus berteroi (Spreng.) Fassett OK4, TX5 sum L.). In May 1996 a whole-lake application of a systemic Echinodorus cordifolius (L.) Griseb. TX5 herbicide [fluridone (1-methyl-3-phenyl-5-[-3(trifluorometh- Eleocharis acicularis (L.) Roemer & J.A. Schultes OK4, TX5 yl) phenyl]-4 (1H)-pyridinone)] eradicated all aquatic plants Eleocharis palustris (L.) Roemer & J.A. Schultes OK4, TX5 from the lake (Lucas et al. 1999). Aquatic plants were still ab- Eleocharis quadrangulata (Michx.) Roemer & J.A. Schultes AL1, OK4, TX5 sent from the lake at the beginning of this study. Justicia americana (L.) Vahl AL1, OK4, TX5 Polygonum hydropiperoides Michx. OK4, TX5 Pontederia cordata L. AL1, OK4, TX5 Construction of Experimental Exclosures Sagittaria graminea Michx. OK4, TX5 Sagittaria latifolia Willd. OK4, TX5 Experimental exclosures were built to protect planted Saururus cernuus L. AL1, OK4 aquatic plants from wave action and herbivory. Each exclo- Scirpus validus Vahl AL1, OK4, TX5 sure was 2 m × 2 m in size and constructed with a 2 m high Submersed species State plastic fence (0.64 cm mesh). Fencing material was support- ed with metal T-posts. Construction of exclosures began in Chara vulgaris L. TX5 October 2000 and was completed in June 2001. We selected Brasenia schreberi J.F. Gmel. TX5 4 5 four locations in the littoral zone of the lake and constructed Ceratophyllum demersum L. OK , TX five exclosures within each location for each experiment (to- Elodea canadensis Michx. OK4 Heteranthera dubia (Jacq.) MacM. OK4, TX2, 3, 5 tal number of exclosures in each location = 10). Experiment Najas guadalupensis (Spreng.) Magnus TX5 1 was designed to evaluate the feasibility of establishing three Nelumbo lutea Willd. AL1, OK4, TX5 species of emergent plants and one submersed species in Nuphar lutea (L.) Sm. OK4, TX5 shallow areas of the littoral zone that dry out during the sum- Nymphaea odorata Ait. OK4, TX5 mer. Exclosures constructed for this experiment were placed Potamogeton illinoensis Morong OK4, TX5 adjacent and parallel to the shoreline, and were located with- Potamogeton nodosus Poir. AL1, OK4, TX2, 3, 5 in littoral zone areas that would be dry when lake levels are Potamogeton pectinatus L. OK4, TX5 0.6 to 0.7 m below the normal lake level of 2.16 m. Experi- Potamogeton pusillus L. TX5 1 4 2, 3, 5 ment 2 was designed to evaluate the feasibility of planting Vallisneria americana Michx. AL , OK , TX submersed aquatic plants in littoral zone areas that are inun- Zannichellia palustris L. TX5 dated all year. Exclosures constructed for experiment 2 were 1Doyle and Smart 1993, 2Doyle et al. 1997, 3Smart et al. 1998, 4Dick et al. also placed parallel to the shoreline, but were positioned fur- 2004a, 5Dick et al. 2004b. ther offshore than exclosures in experiment 1. Specifically, Bolded species are those recommended for use in restoration projects by these exclosures were placed in locations that would have Smart et al. 1996 and Smart et al. 2005. water depths between 0.9 to 1.1 m at the normal lake level. characteristics differed among planting treatments. We eval- Experimental Design and Planting Methods uated planting success by comparing mean percentage cover, stem density,